3GPP Long Term Evolution, LTE, is the fourth-generation mobile communication technology standard developed within the 3rd Generation Partnership Project, 3GPP, to improve the Universal Mobile Telecommunication System, UMTS, standard to cope with future requirements in terms of improved services such as higher data rates, improved efficiency, and lowered costs. The Universal Terrestrial Radio Access Network, UTRAN, is the radio access network of a UMTS and Evolved UTRAN, E-UTRAN, is the radio access network of an LTE system. The Evolved UMTS Terrestrial Radio Access Network, E-UTRAN, consists of base stations called enhanced NodeBs, which may be abbreviated eNBs or eNodeBs, providing the E-UTRA user plane and control plane protocol terminations towards the UE. The eNBs are interconnected with each other by means of the X2 interface. The eNBs are also connected by means of the S1 interface to the Evolved Packet Core, EPC.
Cellular service providers manage their networks, for example, by splitting cells with multiple base stations or adding additional base stations. Typically small cells, e.g. pico cells, are added within the cells in order to off-load the network and to increase coverage. The impact of these actions has an effect on the coverage provided, and the service provider requires knowledge of the impact on the quality of their network.
Existing localized coverage monitoring is either based on crude network-based positioning of data, or global navigation satellite system, global navigation satellite system, GNSS, enabled handsets providing localized measurements. As an example of network-based monitoring, in current cellular systems, service providers detect coverage holes by monitoring dropped calls, logging customer complaints, or having technicians move through the cellular system measuring signal strength.
Examples of GNSS-based localization include dedicated handsets such as TEMS (TEst Mobile System) investigation by Ascom, which is the industry standard tool for GNSS-enabled drive test. Coverage monitoring by means of GNSS-enabled handsets is available in rural to urban areas, but in such areas small cells are typically not deployed, and it is not practical to analyze macro cell coverage unless a large number of wireless devices are participating in the monitoring. This is potentially possible via standardized efforts like Minimization of Drive Tests, but only wireless devices that have provided user consent will participate in the monitoring, which means that it will take a significant time to monitor the macro cell coverage. Coverage monitoring by means of GNSS-enabled handsets is generally not available indoors or in dense urban regions.